Jeep Strokers

Well after questioning some of the fluid engineers at work and emailing a few company's I did the change to synthetic after the break in last night.

I've been running rotella 5w40 synthetic since about 500 miles on build. I've been running 6000 mile oil change intervals, just changed the 3rd time, so there is about 15k miles on the engine now and I just sent an oil sample off for analysis. So we'll see what it says!

Still using the Brad Penn 10w30 racing oil. Still have 60psi cold, 35-40psi warm at idle and then 65-75 at 3K(def. didn't need the high volume pump). I guess I'm gonna stick it out with the BP, but I'm still curious as to what the psi would be(and any power gains) using a 5w20 synthetic(but none have the zddp levels I want).

If your switched your oil at only 500 miles you will have iron deposits and other crap in the analysis. The 4.0L will always show high iron, but having a new engine will make it only worse. Besides.. I'm not sure how much oil analysis are worth anymore. I use Amsoil with 10k change intervals on all the Jeeps (but my pile..yet). On the 4.0L the oil analysis always come back as "change sooner". We put the ZJ on synthetic at 60,000 miles and it is at 190,000 miles with out issues. The 4.7L Wj comes back as less severe. The only vehicle with good analysis are the Jaguars, a 98 XJ8 and a 04 XKR. We have the XKR up to 20,000 miles b/w changes. I'm not sure about 25,000 miles b/w changes yet though.

20k nice, I'm trying for 15k on an 87 BMW 2.5L SOHC I6 (M20B25)

UOA's are best used for trending, meaning having multiples to compare in order to see what's "normal" and what's not. Also very helpful to find other issues, e.g. fuel dilution, coolant, excess H2O, excess dirt etc. And to establish reasonable OCI's of course!

This thread may also help:

http://www.jeepstrokers.com/forum/viewt ... f=24&t=100